If "C1/X" were having multiple uses, the only benefit of this
transformation is to potentially shorten critical path. But it is at the
cost of instroducing additional div.
The additional div may or may not incur cost depending on how div is
implemented. If it is implemented using Newton–Raphson iteration, it dosen't
seem to incur any cost (FIXME). However, if the div blocks the entire
pipeline, that sounds to be pretty expensive. Let CodeGen to take care
this transformation.
This patch sees 6% on a benchmark.
rdar://15032743
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191037 91177308-0d34-0410-b5e6-96231b3b80d8
Based on code review feedback from Eric Christopher, unshifting these
constants as they can appear in the gdb_index itself, shifted a further
24 bits. This means that keeping them preshifted is a bit inflexible, so
let's not do that.
Given the motivation, wrap up some nicer enums, more type safety, and
some utility functions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191035 91177308-0d34-0410-b5e6-96231b3b80d8
Names open to bikeshedding. Could switch back to the constants being
unshifted, but this way seems a bit easier to work with.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191025 91177308-0d34-0410-b5e6-96231b3b80d8
This is how it ignores the dead code:
1) When a dead branch target, say block B, is identified, all the
blocks dominated by B is dead as well.
2) The PHIs of those blocks in dominance-frontier(B) is updated such
that the operands corresponding to dead predecessors are replaced
by "UndefVal".
Using lattice's jargon, the "UndefVal" is the "Top" in essence.
Phi node like this "phi(v1 bb1, undef xx)" will be optimized into
"v1" if v1 is constant, or v1 is an instruction which dominate this
PHI node.
3) When analyzing the availability of a load L, all dead mem-ops which
L depends on disguise as a load which evaluate exactly same value as L.
4) The dead mem-ops will be materialized as "UndefVal" during code motion.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191017 91177308-0d34-0410-b5e6-96231b3b80d8
Various Windows SDK headers use _MSC_VER values to figure out what
version of the VC++ headers they're using, in particular for SAL macros.
Patch by Paul Hampson!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191015 91177308-0d34-0410-b5e6-96231b3b80d8
Adds a flag to the MemorySanitizer pass that enables runtime rewriting of
indirect calls. This is part of MSanDR implementation and is needed to return
control to the DynamiRio-based helper tool on transition between instrumented
and non-instrumented modules. Disabled by default.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191006 91177308-0d34-0410-b5e6-96231b3b80d8
When selecting the DAG (add (WrapperRIP ...), (FrameIndex ...)), X86 code had
spotted the FrameIndex possibility and was working out whether it could fold
the WrapperRIP into this.
The test for forming a %rip version is notionally whether we already have a
base or index register (%rip precludes both), but we were forgetting to account
for the register that would be inserted later to access the frame.
rdar://problem/15024520
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190995 91177308-0d34-0410-b5e6-96231b3b80d8
This puts all the global PassManager debugging flags, like
-print-after-all and -time-passes, behind a managed static. This
eliminates their static initializers and, more importantly, exit-time
destructors.
The only behavioral change I anticipate is that tools need to
initialize the PassManager before parsing the command line in order to
export these options, which makes sense. Tools that already initialize
the standard passes (opt/llc) don't need to do anything new.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190974 91177308-0d34-0410-b5e6-96231b3b80d8
1) make sure that the first two instructions of the sequence cannot
separate from each other. The linker requires that they be sequential.
If they get separated, it can still work but it will not work in all
cases because the first of the instructions mostly involves the hi part
of the pc relative offset and that part changes slowly. You would have
to be at the right boundary for this to matter.
2) make sure that this sequence begins on a longword boundary.
There appears to be a bug in binutils which makes some of these calculations
get messed up if the instruction sequence does not begin on a longword
boundary. This is being investigated with the appropriate binutils folks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190966 91177308-0d34-0410-b5e6-96231b3b80d8
Use the DIVariable::isIndirect() flag set by the frontend instead of
guessing whether to set the machine location's indirection bit.
Paired commit with CFE.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190961 91177308-0d34-0410-b5e6-96231b3b80d8
advertised - but it does have the caveat that calls to DynamicLibrary::AddSymbol will
"reset" if you shutdown llvm and try to come back for seconds. This is a subtle
behavior change, but I'm assuming that nobody is affected by it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190946 91177308-0d34-0410-b5e6-96231b3b80d8
XCore target: Add XCoreTargetTransformInfo
This is where getNumberOfRegisters() resides, which in turn returns the
number of vector registers (=0).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190936 91177308-0d34-0410-b5e6-96231b3b80d8
For some reason I never got around to adding these at the same time as
the signed versions. No idea why.
I'm not sure whether this SystemZII::BranchC* stuff is useful, or whether
it should just be replaced with an "is normal" flag. I'll leave that
for later though.
There are some boundary conditions that can be tweaked, such as preferring
unsigned comparisons for equality with [128, 256), and "<= 255" over "< 256",
but again I'll leave those for a separate patch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190930 91177308-0d34-0410-b5e6-96231b3b80d8
advertised - but it does have the caveat that calls to DynamicLibrary::AddSymbol will
"reset" if you shutdown llvm and try to come back for seconds. This is a subtle
behavior change, but I'm assuming that nobody is affected by it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190921 91177308-0d34-0410-b5e6-96231b3b80d8
If address space 0 was smaller than the address space
in a constant inttoptr/ptrtoint pair, the wrong mask size
would be used.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190899 91177308-0d34-0410-b5e6-96231b3b80d8
